1. Field of the Invention
This invention relates to a pipe coupling arrangement. More particularly, the invention relates to a pipe coupling arrangement which is adapted for coupling various types of pipes with each other.
2. Description of the Prior Art
There are hitherto conventional pipe coupling arrangements as shown in Japanese Patent Laid-Open No. 57-161391 and Japanese Utility Model Laid-Open No. 60-24990.
FIG. 8(a) illustrates one arrangement of the type in accordance with the invention described in Japanese Patent Laid-Open No. 57-161391, wherein a plurality of threaded holes 15 are arranged in the outer periphery of a coupling body 1b in the circumferencial direction thereof with predetermined spacing; a locking screw 16 is screwed into a threaded hole 15 of the coupling body 1b; a ring-shaped chip 17, which is disposed in the threaded hole 15 under urged condition and pressed on the back thereof by the locking screw 16; annular cutting edges 18, which are respectively formed at inner circumferential edges of opposed ends of the chip 17 and bite the outer periphery of a pipe C by the downward movement of the locking screw 16 such that a pair of pipes C are connected with one another.
FIG. 8(b) illustrates another arrangement of the type in accordance with the invention described in Japanese Utility Model Laid-Open No. 60-24990, wherein an internally threaded hole 19 is formed at an internal periphery of one end of a coupling body 1c; an annular set screw 20 screwed into the internally threaded hole 19; a ring shaped chip 17, which is disposed on an outer periphery of a pipe C closer to an end thereof and pressed on the back thereof by a tapered portion 21 formed on an end of the set screw 20; cutting edges 18, which are respectively formed at inner circumferential edges of opposed ends of the chip 17 and bite the outer circumferential surface of the pipe C by the axial movement of the set screw 20, thus connecting a pair of pipes C with one another.
However, there are inherent problems in both arrangements as shown in FIG. 9, wherein when the pipe C is inserted into the coupling body 1b or the like. The pipe C is frequently positioned biaxially or eccentrically with regard to the coupling body 1b. Under such condition, screwing the locking screw 16 into the threaded hole 15 and pressing the same on the back of the chip 17 leads to poor biting of the cutting edges 18 onto the outer periphery of the pipe C. Accordingly, a packing 24 can not effectively seal the pipes C, thus leading to the fluid leakage. Such unintentional misalignment of the pipe C and the coupling 1b may result in accidental separation thereof, which is a fatal problem for the arrangement of this type. In addition, it is required to force the locking screw 16 into the threaded hole 15, pushing against the resiliently outward force of the chip 17, which makes the screwing operation troublesome, resulting in poor biting of the cutting edges onto the outer periphery of the pipe C.
Furthermore, in the latter arrangement as illustrated in FIG. 8(b), since the set screw 20 is screwed into the internally threaded portion 19 of the coupling body 1c, that arrangement may cause misalignment of the pipe C and the coupling body 1c, the uncompleted screwing of the set screw 20 into the internally threaded portion 19, and the subsequent poor pressing of the chip 17 onto the outer periphery of the pipe C due to the resiliently outward force of the chip 17 in the event of the deformation of the pipe C per se. All in all, this results in disadvantages such as fluid leakage and potential accidental separations of the tube C from the coupling body 1c.
In addition to the troublesome work in screwing the set screw 20 into the internally threaded portion 20, the threading of the set screw 20 or the like in manufacturing steps is a troublesome and time-consuming process, which leads to rising manufacturing costs.
Accordingly, the main object of the present invention is to provide a pipe coupling arrangement, which facilitates an easy coupling operation, and the secure and tight coupling of a pipe.